ASCLEPIADACEAE

This family consists of 1,700 species, in about 220 genera, of perennial plants, (often climbing shrubs), with milky sap. They are mostly tropical, especially those in Africa, but there are also a few temperate species of which a common one is the swan plant, Gomphocarpus fruticosus, grown in many primary schools to feed monarch butterfly caterpillars.

Leaves usually opposite, sometimes spiral, simple, entire and without stipules.

Flowers usually in many-flowered cymes, racemes or umbels, regular and perfect, with parts in 5's—sepals free, petals joined, stamens 5, carpels 2, united into a gynostegium. Insect pollinated.

Asclepias tuberosa

Pleurisy root, butterfly weed

Description

Perennial growing 30 cm-1 m × 1 m with round, stout, hairy stems almost or entirely devoid of milky juice and a fleshy, spindle-shaped rhizome with a knotted crown. Leaves more or less spiral and crowded, lanceolate-oblong, to 10 cm long, sessile, dark green. Flowers in many flowered, flat-topped umbels in upper leaf axils, bright orange, sometimes red or yellow, blooming in summer. Fruit a long pod containing many dark seeds each with a silky pappus.

Family Asclepiadaceae

Habitat and cultivation

Native to North America from New England to North Dakota and south to Florida, Arizona and North Mexico, growing from seed in open, sunny areas of rich, peaty soils. It blooms from spring to autumn and is frost resistant but drought tender.

Parts used

The root.

Active constituents

1) Steroidal glycosides:-

a) an adrostane—ascandroside

b) cardenolides including glycosides of δ-5-calotropin, uzarigenin, coroglaucigenin and corotoxigenin1

c) pregnane glycosides including ikemagenin, lineolon and pleurogenin²

2) Flavonoids including rutin, kaempferol and quercitin

3) Essential oil

Also contains friedalin, triterpenes (α- and β-amyrin, lupeol), viburnitol, choline sugars and amino acids.

The constituents of this herb are not well characterised.

Actions

1) Diaphoretic

2) Expectorant

3) Antispasmodic

4) Carminative

Scientific information

The root, which was an official drug in the US Pharmacopoeia from 1820–1890, was used for the treatment of asthma and bronchitis.³

The pharmacology of this herb is not well studied but it does achieve clinical results. Pregnane glycosides can affect fat metabolism and they are being studied in this context albeit from other plant sources.

Potter's states that it has been used for uterine disorders. However its folklore name gives the main current usage.

Medicinal uses

Respiratory tract

All actions are ideal for the treatment of lung problems and any associated fever:

• pleurisy (BHP specific)
• bronchitis
• pneumonia
• influenza

Pharmacy

Three times daily
Decoction dried root	–   1–4 g
Tincture 1:10 (45%)	–   1–5 ml
Fluid Extract (45%)	–   1–4 ml

Precautions and/or safety

Large doses may cause diarrhoea and vomiting.

Historical uses

Also used for pulmonary catarrh and consumption; diarrhoea and dysentery; infantile colic; headaches; mumps and measles; acute and chronic rheumatism; typhoid; eczema. Externally a poultice of the root was used traditionally to treat bruises, swelling, rheumatism and lameness.